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Stupid question about daisy-chaining cabs

Discussion in 'Amps and Cabs [BG]' started by Invisible_Kid, Apr 1, 2013.


  1. Invisible_Kid

    Invisible_Kid

    Jun 1, 2010
    I know there is a huge thread containing links to all sorts of things covering ohms, but I couldn't find an answer to this.
    If you're daisy chaining two cabs together, do you add the impedences as you would resistors in a series (a 4 ohm extension to an 8 ohm cab would be 12 total ohms) and then use that new value in the impedence formula, being 1/n = (1/a + 1/b + 1/c ...)?
    Ex.
    A stack has three cabs. Two 8 ohm cabs are wired normally (in parallel) and one has a 4 ohm cab daisy chained to it.
    1/n = 1/8 + 1/b
    b = 8 + 4 = 12
    1/n = 1/8 + 1/12
    1/n = 5/24
    n = 4.8 ohms
    Is that correct?
     
  2. Without actually seeing your setup, I can't be sure of this. Are all of your cabs being powered from the same output? Seems like a lot of boxes, are you not getting enough grunt from the two 8 ohm cabs?
     
  3. The chaining through a cab is still parallel! You need a special cable to run series.

    You will net a 2 ohm load.
     
  4. smogg

    smogg

    Mar 27, 2007
    NPR, Florida
    I'm not crazy, I'm just a little unwell
    8 ohm + 4 ohm = 2.67 ohms
    8 + 8 + 4 = 2 ohms
     
  5. RickenBoogie

    RickenBoogie

    Jul 22, 2007
    Dallas, TX
    +1 daisy-chaining from one cab to another is still a parallel connection, and the above set up will net a 2 ohm load.
     
  6. mmbongo

    mmbongo Dilly Dilly! Supporting Member

    Aug 5, 2009
    Carolinas
    Plus the 4 ohm cabinet will recieve twice the power as either of the 8 ohm cabinets. Not a good idea.
     
  7. Invisible_Kid

    Invisible_Kid

    Jun 1, 2010
    Thank you.
     
  8. MarkBG

    MarkBG

    Mar 2, 2009
    Correct: Not a good idea. If daisychaining ,best to use all cabs having the same impedance for even power distribution,at least theoretically speaking.

    Other issue in your case is you are down to 2ohms. Many amps cannot tollarate 2 ohms, and usually will require not going below 4ohms.
     
  9. I disagree. It could be a PERFECT idea. It depends entirely on the speakers. For example, lets say cabinet 1 is an 8-ohm 12, cabinet 2 is an 8-ohm 12, and cabinet 3 has 2 8-ohm 12s for 4 ohms. You have four 8-ohm 12s all in parallel and that presents a 2 ohms to the amp.

    Another possibility : cabs 1 and 2 are four 32-ohm 10s for 8 ohms each and cabinet 3 is eight 32-ohm 10s for 4 ohms. Again, 2 ohm to the amp and, as an added bonus, equal power to all speakers.

    It could work out perfectly.
     
  10. Invisible_Kid

    Invisible_Kid

    Jun 1, 2010
    As a follow up to this, what if I put the same cab in twice? Allow me to explain myself.
    I have a 150W 1x15 and a 550W 4x10. The 4x10 has two 275W inputs. Could I plug each cab in normally, then use a cable from the "extension" port of the 1x15 to the second 275W input of the 4x10? I have a 500W head, if it matters.
     
  11. Unless that cab is a "stereo" cab (each input ONLY feeds 2 speakers), then NO

    If you are assuming that a 550watt cab that has two inputs only gets half it's rating if you plug into ne input, you are wrong.
     
  12. What are the exact cabs, their impedances, and the amp you are using?
     
  13. Yes lets stop playing games here.

    You have not gotten the idea yet, as far as wattage that is what your amp head puts out. Period. The cabs can either accept that wattage without burn-out or go up in smoke. Cabs can not magically split up the wattage. How much power goes where is a function of impedance to signal flow (high numbers mean they impede the flow more so they get less from the amp head, they can't load the amp as much).
     
  14. dcarwin

    dcarwin

    Feb 11, 2013
    415
    What if the four ohm cab is an acme, and you want it to have more power?
     

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